A portable solar recharger — for your car

The electric car charging station from Envision Solar doesn’t need to be plugged in to the power grid. Nor does it need to be bolted to the ground or cemented in place. It is completely self-contained, getting all its electricity from a big solar panel while its heavy steel base keeps it in place.

And it’s coming to San Francisco.

Envision will deploy three ARCs in the city, moving them periodically to see how much use they get in different settings. The company displayed one ARC, short for Autonomous Renewable Charger, near San Francisco’s UN Plaza on Monday as part of the annual EV Week event promoting plug-in transportation.

“These EV ARCS will allow San Franciscans to drive on sunshine and drive for free, assuming they’re intelligent enough to have an electric car,” said Desmond Wheatley, CEO of Envision, which is based in San Diego.

Installing an electric vehicle charging station in a parking lot or along a city street typically requires tearing up the pavement to lay a cable to the nearest electrical line. Most cities demand a permit for that kind of work, adding time and expense. The ARC, in contrast, can be installed in 2 minutes, Wheatley said.

Its steel base, weighing about 11,000 pounds, keeps it anchored even in high winds. And the base’s dimensions — 8 feet by 18 feet — fit most parking slots. Electric cars simply roll onto the base and plug in, although on Monday, the company kept the car parked to the side to give the public a better view.

The solar panel, which tilts to track the sun, stores its electricity in a battery pack made by AllCell Technologies of Chicago. The battery pack, in turn, feeds a level-two charger.

The ARC’s San Francisco deployment will be funded by a grant from the Schmidt Family Foundation (that’s Eric and Wendy Schmidt, of Google fame). The non-profit group Charge Across Town, which applied for the grant, will help pick locations, working with several city departments. The plan calls for moving each station every three months in a kind of rolling experiment.